The present invention relates to tires for two-wheeled vehicles. More particularly, the invention is concerned with tires for two-wheeled vehicles which produce reduced vibration during running, have superior running stability, are lightweight, and, furthermore, are superior in durability and impact resistance.
Requirements for tires for two-wheeled vehicles, especially tires for racing bicycles, include reduced vibration (with respect to ordinary tires of the same general type) during running, good running stability, light weight, and the ability to withstand high-speed running.
These characteristics are required particularly for racing bicycles. For racing, circular tires having a ring-like form in cross section are ordinarily employed. Minimizing the running resistance is of course the primary concern for this purpose. Efforts have been made to produce lightweight tires by reducing the thickness of the tread rubber. Such minimization of running resistance and reduction of weight are also of value for ordinary bicycle tires.
Reducing the thickness of the tread rubber, however, increases the danger of puncturing the tire if a large impact is applied thereto or if the tire is run over a sharp-pointed object such as broken glass, a nail, or the like. In order to overcome this problem, a fabric, for example, of aromatic polyamide or polyester fibers, can be inserted as a reinforcing material between the tread rubber and the carcass layer. This reinforcing material, however, increases the weight of the tire and the running resistance. Moreover, if the adhesion between the reinforcing material and the carcass layer or between the reinforcing material and the tread rubber is poor, layer separation between the reinforcing material and the carcass layer or between the reinforcing material and the tread rubber can occur during running. In addition, a problem arises in that the durability of the tire is reduced by fatigue deterioration of the reinforcing material due to compression and stretching.